For me, it's blast-off.
Via Metafilter, where folks are a bit younger, since they're getting things like air guitar or downloadable.
"Blast-off" as a noun signifying the launching of a rocket doesn't appear in the NYT archive until March 1952, but there are many instances of the word pair "blast off" before then, mostly to refer to storms — "a blast off the Greenland coast" — and hits in baseball — "a blast off the right-field wall." The 1952 article is titled "'Space Fever' Hits the Small-Fry; If your boy talks gibberish or hisses like a boiler, don't worry -- he's just cosmic."
The hissing represents rocket-ship take-off, and the gibberish is space-ship argot.
In apartment-house elevators, space-talk breaks out in commands like "Blast off!" when a lift starts upward, and "Brake your jets!" as an elevator comes to a landing. On auto rides, small-fry lean out alternate windows shrilling "Blast the port tube!" and "Blow the starboard rocket!"...
The space-conscious don't say "Scram"; They say "Blast off, chum!" They don't call a companion "screwy"; they say "Steady your gyros." A reproof or tongue-lashing draws the remark: "Boy, did I get my tubes scorched!"; and anyone who wanders off the point is told, "You're way out of your orbit."